DKK3 blocked translocation of β-catenin/EMT induced by hypoxia and improved gemcitabine therapeutic effect in pancreatic cancer Bxpc-3 cell

Dkk3 inhibits the aggressiveness and mitigates chemoresistance through low lipid droplet formation in gastric cancer: A biomarker and gene therapy target

Dkk3 is discovered through comparative studies of immortalized cells and their parental counterparts and might inhibit the aggressive phenotypes in malignant cells, demonstrating its tumor-suppressor activity. Here, we explored the clinicopathological significance of Dkk3 expression, the association between Dkk3 expression and immune microenvironment, and Dkk3-related signal pathways in gastric cancer (GC), and discovered the effects of Dkk3 on aggressiveness, chemoresistance and lipid droplet formation with molecular mechanisms investigated. Our data showed that plasma level of Dkk3 was low in GC and Dkk3 expression was negatively correlated with younger age, tumor size, depth of invasion, lymph node metastasis, clinicopathological stage and histological classification of GC. Additionally our study shows DKK3 have a potential impact on GC immunity by regulating immune cell infiltration. Overexpression of wild-type and no-signal peptide Dkk3 inhibited cell proliferation, promoted apoptotic and pyroptotic cell death, and suppressed invasion, migration and epithelial-mesenchymal transition in GC cells. Furthermore, Dkk3 expression promoted chemosensitivity by weakening lipid droplet formation in GC cells. The Dkk3-related pathways included ECM (extracellular matrix)-receptor interactions, ECM constituents and organization, WP miRNA targets in ECM membrane receptors, focal adhesion, cAMP, calcium and integrin signaling pathways, basement membranes, spliceosome activity, mitochondrial oxidative phosphorylation, and ubiquitin-like protein binding. These results indicate that Dkk3 expression may serve as a valuable indicator to evaluate the pathological behaviors and immunotherapy of GC. Additionally, Dkk3 could potentially inhibit the aggressiveness regardless of signal peptide, and alleviate chemoresistance by low lipid droplet formation, making it become a valuable molecular target for gene therapy.

Advances and insights for DKK3 in non-cancerous diseases: a systematic review

This review delves into the role of Dickkopf-3 (DKK3), a secreted glycoprotein and member of the Dickkopf family, in non-malignant diseases. DKK3 is particularly known for its regulatory effects on the Wnt signaling pathway, a critical mediator in various biological processes including cell proliferation, differentiation, and migration. Our review highlights DKK3's influence in disorders of the cardiovascular, respiratory, renal, and muscular systems, where it contributes to disease progression by modulating these key biological processes. As an emerging biomarker, DKK3's levels have been found to correlate with various disease states, underscoring its potential diagnostic and therapeutic implications.

Epithelial splicing regulatory protein 1 promotes peritoneal dissemination of ovarian cancer by inducing the formation of circular RNAs modulating epithelial plasticity

Peritoneal metastases prevalently occur in ovarian cancer, deteriorating patient prognosis. During the metastatic cascade, tumor plasticity enables cells to adapt to environmental changes, thereby facilitating dissemination. We previously found that epithelial splicing regulatory protein 1 (ESRP1) is linked to peritoneal metastasis and epithelial-mesenchymal plasticity in ovarian cancer. This study delves into the underlying mechanism. We found that ESRP1 preserves epithelial plasticity in ovarian cancer cells in vitro and in vivo. Functionally, ESRP1 enhances ovarian cancer cell growth and peritoneal dissemination. High-throughput sequencing revealed several ESRP1-related epithelial RNAs, encompassing both linear and circular forms. Specifically, ESRP1 triggers the cyclization of circPAFAH1B2 and circUBAP2 through binding to the GGU sequences in adjacent introns. The two ESRP1-induced circular RNAs stabilize DKK3 and AHR mRNAs, which are critical for epithelial plasticity, through interaction with IGF2BP2. Collectively, ESRP1 triggers the formation of circPAFAH1B2 and circUBAP2, which in turn stabilizes DKK3 and AHR through IGF2BP2 binding, thereby modulating the epithelial plasticity and aiding the peritoneal spread of ovarian cancer cells. The findings unveiled a biological network, orchestrated by ESRP1, that governs the epithelial-mesenchymal plasticity of ovarian cancer cells, emphasizing the therapeutic potential of ESRP1 and its induced circular RNAs for ovarian cancer treatment.

Unraveling the Multifaceted Role of the miR-17-92 Cluster in Colorectal Cancer: From Mechanisms to Biomarker Potential

Colorectal cancer (CRC) is a complex disease driven by intricate mechanisms, making it challenging to understand and manage. The miR-17-92 cluster has gained significant attention in CRC research due to its diverse functions and crucial role in various aspects of the disease. This cluster, consisting of multiple individual miRNAs, influences critical processes like tumor initiation, angiogenesis, metastasis, and the epithelial-mesenchymal transition (EMT). Beyond its roles in tumorigenesis and progression, miR-17-92's dysregulation in CRC has substantial implications for diagnosis, prognosis, and treatment, including chemotherapy responsiveness. It also shows promise as a diagnostic and prognostic biomarker, offering insights into treatment responses and disease progression. This review provides a comprehensive overview of recent advancements and the context-dependent role of the miR-17-92 cluster in colorectal cancer, drawing from the latest high-quality published data. It summarizes the established mechanisms governing miR-17-92 expression and the molecular pathways under its influence. Furthermore, it examines instances where it functions as an oncogene or a tumor suppressor, elucidating how cellular contexts dictate its biological effects. Ultimately, miR-17-92 holds promise as a biomarker for prognosis and therapy response, as well as a potential target for cancer prevention and therapeutic interventions. In essence, this review underscores the multifaceted nature of miR-17-92 in CRC research, offering promising avenues for enhancing the management of CRC patients.

HCV Core protein represses DKK3 expression via epigenetic silencing and activates the Wnt/β-catenin signaling pathway during the progression of HCC

The Wnt/β-catenin signaling pathway is frequently activated in hepatocellular carcinoma (HCC). A number of studies have focused on the aberrant hypermethylation of the DKK family proteins and its role in regulating the activation of specific signaling pathways. However, the exact way by which DKK regulates the signaling pathway caused by Core protein of HCV has not been reported. In the present study, we evaluated the expression level of DKK and its aberrant promoter methylation to investigate the involvement of epigenetic regulation in hepatoma cell lines. The transcription and protein expression of DKK1 was significantly increased, whereas the transcription and protein expression levels of DKK2, DKK3, and DKK4 were significantly decreased following overexpression of Core protein. Pyrosequencing indicated that hypermethylation of DKK3 was increased. This was associated with increased expression of Dnmt1. The investigation of the molecular mechanism indicated that HCV Core protein interacted with Dnmt1, which combined with the promoter of DKK3, leading to methylation of DKK3. Functional studies indicated that Core protein promoted the growth, migration and invasion of cancer cells. However, upregulation of the expression of DKK3 and/or the knockdown of the expression of Dnmt1 inhibited the growth, migration and invasion of cancer cells. Taken together, the data indicated that epigenetic silencing of DKK3 caused by Dnmt1 activated the Wnt/β-catenin pathway in HCV Core-mediated HCC. Therefore, DKK3 may be a potential diagnostic and therapeutic target for HCC.

Dickkopf-related protein 3 alters aerobic glycolysis in pancreatic cancer BxPC-3 cells, promoting CD4+ T-cell activation and function

Background

To investigate the value of Dickkopf-related protein 3 (DKK3) on aerobic glycolysis in pancreatic cancer cells, where DKK3-overexpression is used to determine its effects on CD4⁺ T cells.

Methods

The BxPC-3-DKK3 cell line was constructed, and peripheral blood mononuclear cell (PBMC) was prepared. After isolated the CD4⁺ T cells, the lactic acid, glucose uptake ability, cellular viability, proliferation, apoptosis, and markers were detected by PCR and western blot, and the concentrations of multiple cytokines were determined using the ELISA method.

Results

After co-culture with pancreatic cancer cells overexpressing DKK3, the glucose uptake markedly, proliferation enhanced and apoptosis inhibited in CD4⁺ T cells. The co-culture model also revealed that DKK3-overexpression promotes the activation and regulates the metabolism and function of CD4⁺ T cells.

Conclusions

DKK3 alters the metabolic microenvironment of pancreatic cancer cells and further facilitates the function of CD4⁺

T cells which suggesting that DKK3 may have a therapeutic potential in pancreatic cancer.

Functional Genomic Screening During Somatic Cell Reprogramming Identifies DKK3 as a Roadblock of Organ Regeneration

Somatic cell reprogramming and tissue repair share relevant factors and molecular programs. Here, Dickkopf-3 (DKK3) is identified as novel factor for organ regeneration using combined transcription-factor-induced reprogramming and RNA-interference techniques. Loss of Dkk3 enhances the generation of induced pluripotent stem cells but does not affect de novo derivation of embryonic stem cells, three-germ-layer differentiation or colony formation capacity of liver and pancreatic organoids. However, DKK3 expression levels in wildtype animals and serum levels in human patients are elevated upon injury. Accordingly, Dkk3-null mice display less liver damage upon acute and chronic failure mediated by increased proliferation in hepatocytes and LGR5+ liver progenitor cell population, respectively. Similarly, recovery from experimental pancreatitis is accelerated. Regeneration onset occurs in the acinar compartment accompanied by virtually abolished canonical-Wnt-signaling in Dkk3-null animals. This results in reduced expression of the Hedgehog repressor Gli3 and increased Hedgehog-signaling activity upon Dkk3 loss. Collectively, these data reveal Dkk3 as a key regulator of organ regeneration via a direct, previously unacknowledged link between DKK3, canonical-Wnt-, and Hedgehog-signaling.

microRNA-377-3p inhibits osteosarcoma progression by targeting CUL1 and regulating Wnt/β-catenin signaling pathway

OBJECTIVE

Emerging studies highlight the crucial effects of microRNAs on cancer initiation and malignant progression of various tumors. This study focused on the biological effect of miR-377-3p on CUL1 and epithelial-mesenchymal transition (EMT) and Wnt/β-catenin pathways in osteosarcoma (OS).

METHODS

We performed quantitative real-time polymerase chain reaction (qRT-PCR) to analyze miR-377-3p and CUL1 expression levels in OS tissues and MG-63 cells. Then, cell counting kit (CCK)-8 and Transwell assay were used to examine the functions of miR-377-3p in OS cell growth and metastasis abilities. Meanwhile, luciferase reporter assay was used to validate CUL1 as direct target of miR-377-3p. qRT-PCR and Western blot were then carried out to detect the impact of miR-377-3p on EMT and Wnt/β-catenin pathways. Tumor xenograft models were established to further examine the effects of miR-377-3p on OS tumorigenesis in vivo.

RESULTS

miR-377-3p downregulation was frequently identified in OS tissues and cells, which was associated with worse prognosis of OS patients. Functional experiments showed miR-377-3p restoration could dramatically repress OS cell growth and migration by regulation of EMT and Wnt/β-catenin pathways. Moreover, luciferase reporter assay revealed that CUL1 acted as a functional target of miR-377-3p. Additionally, the elevated CUL1 expressions in OS tissues also indicated poor prognosis of OS patients. Furthermore, the OS tumor growth was also obviously inhibited by miR-377-3p overexpression in vivo.

CONCLUSIONS

Collectively, all the above findings revealed that miR-377-3p exerted anti-OS functions via CUL1 and EMT and Wnt/β-catenin pathways. These results may contribute to the development of clinical OS treatment.

Targeting hypoxic tumor microenvironment in pancreatic cancer

Attributable to its late diagnosis, early metastasis, and poor prognosis, pancreatic cancer remains one of the most lethal diseases worldwide. Unlike other solid tumors, pancreatic cancer harbors ample stromal cells and abundant extracellular matrix but lacks vascularization, resulting in persistent and severe hypoxia within the tumor. Hypoxic microenvironment has extensive effects on biological behaviors or malignant phenotypes of pancreatic cancer, including metabolic reprogramming, cancer stemness, invasion and metastasis, and pathological angiogenesis, which synergistically contribute to development and therapeutic resistance of pancreatic cancer. Through various mechanisms including but not confined to maintenance of redox homeostasis, activation of autophagy, epigenetic regulation, and those induced by hypoxia-inducible factors, intratumoral hypoxia drives the above biological processes in pancreatic cancer. Recognizing the pivotal roles of hypoxia in pancreatic cancer progression and therapies, hypoxia-based antitumoral strategies have been continuously developed over the recent years, some of which have been applied in clinical trials to evaluate their efficacy and safety in combinatory therapies for patients with pancreatic cancer. In this review, we discuss the molecular mechanisms underlying hypoxia-induced aggressive and therapeutically resistant phenotypes in both pancreatic cancerous and stromal cells. Additionally, we focus more on innovative therapies targeting the tumor hypoxic microenvironment itself, which hold great potential to overcome the resistance to chemotherapy and radiotherapy and to enhance antitumor efficacy and reduce toxicity to normal tissues.

Novel therapies targeting hypoxia mechanism to treat pancreatic cancer

Pancreatic cancer (PC) is one of the deadliest malignancies. The high mortality rate of PC largely results from delayed diagnosis and early metastasis. Therefore, identifying novel treatment targets for patients with PC is urgently required to improve survival rates. A major barrier to successful treatment of PC is the presence of a hypoxic tumor microenvironment, which is associated with poor prognosis, treatment resistance, increased invasion and metastasis. Recent studies have identified a number of novel molecules and pathways in PC cells that promote cancer cells progression under hypoxic conditions, which may provide new therapy strategies to inhibit the development and metastasis of PC. This review summarizes the latest research of hypoxia in PC and provides an overview of how the current therapies have the capacity to overcome hypoxia and improve PC patient treatment. These findings will eventually provide guidance for future PC management and clinical trials and hopefully improve the survival of patients with PC.

Role of DNA Methylation in the Resistance to Therapy in Solid Tumors

Despite the recent advances in chemotherapeutic treatments against cancer, some types of highly aggressive and invasive cancer develop drug resistance against conventional therapies, which continues to be a major problem in the fight against cancer. In recent years, studies of alterations of DNA methylome have given us a better understanding of the role of DNA methylation in the development of tumors. DNA methylation (DNAm) is an epigenetic change that promotes the covalent transfer of methyl groups to DNA. This process suppresses gene expression through the modulation of the transcription machinery access to the chromatin or through the recruitment of methyl binding proteins. DNAm is regulated mainly by DNA methyltransferases. Aberrant DNAm contributes to tumor progression, metastasis, and resistance to current anti-tumoral therapies. Aberrant DNAm may occur through hypermethylation in the promoter regions of tumor suppressor genes, which leads to their silencing, while hypomethylation in the promoter regions of oncogenes can activate them. In this review, we discuss the impact of dysregulated methylation in certain genes, which impact signaling pathways associated with apoptosis avoidance, metastasis, and resistance to therapy. The analysis of methylome has revealed patterns of global methylation, which regulate important signaling pathways involved in therapy resistance in different cancer types, such as breast, colon, and lung cancer, among other solid tumors. This analysis has provided gene-expression signatures of methylated region-specific DNA that can be used to predict the treatment outcome in response to anti-cancer therapy. Additionally, changes in cancer methylome have been associated with the acquisition of drug resistance. We also review treatments with demethylating agents that, in combination with standard therapies, seem to be encouraging, as tumors that are in early stages can be successfully treated. On the other hand, tumors that are in advanced stages can be treated with these combination schemes, which could sensitize tumor cells that are resistant to the therapy. We propose that rational strategies, which combine specific demethylating agents with conventional treatment, may improve overall survival in cancer patients.

MicroRNAs target the Wnt/β‑catenin signaling pathway to regulate epithelial‑mesenchymal transition in cancer (Review)

Epithelial‑mesenchymal transition (EMT), during which cancer cells lose the epithelial phenotype and gain the mesenchymal phenotype, has been verified to result in tumor migration and invasion. Numerous studies have shown that dysregulation of the Wnt/β‑catenin signaling pathway gives rise to EMT, which is characterized by nuclear translocation of β‑catenin and E‑cadherin suppression. Wnt/β‑catenin signaling was confirmed to be affected by microRNAs (miRNAs), several of which are down‑ or upregulated in metastatic cancer cells, indicating their complex roles in Wnt/β‑catenin signaling. In this review, we demonstrated the targets of various miRNAs in altering Wnt/β‑catenin signaling to promote or inhibit EMT, which may elucidate the underlying mechanism of EMT regulation by miRNAs and provide evidence for potential therapeutic targets in the treatment of invasive tumors.

Hypoxia and pancreatic ductal adenocarcinoma

Chemotherapy and immunotherapy for pancreatic ductal adenocarcinoma (PDAC) have limited success. One reason for this is thought to be the cancer microenvironment surrounding PDAC. Hypoxia is a feature of the cancer microenvironment. Under hypoxia, different various molecules and signaling pathways are activated compared with normoxia. To develop a new effective therapeutic strategy for PDAC, we need to target these hypoxic conditions to overcome PDAC. To inhibit the malignant phenotype, the cellular changes that occur under hypoxia should be elucidated. Various molecules and signaling that are activated by hypoxia may contribute to the induction of malignant phenotypes of PDAC such as proliferation, invasion, tumorigenesis, chemosensitivity, and autophagy. If we can develop therapeutic approaches to target one of these molecules or signaling pathways, we may proceed to the next therapeutic step of successfully treating refractory PDAC.

MiR-425 Promotes Migration and Invasion in Bladder Cancer by Targeting Dickkopf 3

Background: Bladder cancer (BC) is a common malignancy with high morbidity and mortality. MicroRNAs (miRNAs) are critical post-transcriptional regulators in various cancers. This study aimed to investigate the effect of miR-425 on the migration and invasion of BC.

Methods: The expression of miR-425 and Dickkopf 3 (DKK3) was examined in clinical BC specimens. T24 and 5637 BC cell lines were employed and transfected with miR-425 inhibitors. The correlation between miR-425 and DKK3 was determined by a luciferase reporter assay. Cell migration and invasion capacity were measured by wound healing and Transwell assays. The expression levels of DKK3, E-cadherin, N-cadherin and vimentin were analysed by Western blotting and qRT-PCR.

Results: miR-425 was negatively correlated with the expression of DKK3 in clinical BC specimens. Further studies identified DKK-3 as a direct target of miR-425. Moreover, knockdown of miR-425 promoted the expression of DKK3 and suppressed cell migration and invasion capacity. miR-425 silencing increased E-cadherin levels but decreased vimentin and N-cadherin protein levels in T24 and 5637 cells.

Conclusion: Our study indicated that miR-425 promoted the migration and invasion of BC via targeting DKK3.

Angioregulatory microRNAs in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer mortality. Angiogenesis is a rate-determining step in CRC development and metastasis. The balance of angiogenic and antiangiogenic factors is crucial in this process. Angiogenesis-related genes can be regulated post-transcriptionally by microRNAs (miRNAs) and some miRNAs have been shown to shuttle between tumor cells and the tumor microenvironment (TME). MiRNAs have context-dependent actions and can promote or suppress angiogenesis dependent on the type of cancer. On the one hand, miRNAs downregulate anti-angiogenic targets and lead to angiogenesis induction. Tumor suppressor miRNAs, on the other hand, enhance anti-angiogenic response by targeting pro-angiogenic factors. Understanding the interaction between these miRNAs and their target mRNAs will help to unravel molecular mechanisms involved in CRC progression. The aim of this article is to review the current literature on angioregulatory miRNAs in CRC.

Targeting Epithelial Mesenchymal Plasticity in Pancreatic Cancer: A Compendium of Preclinical Discovery in a Heterogeneous Disease

Pancreatic Ductal Adenocarcinoma (PDAC) is a particularly insidious and aggressive disease that causes significant mortality worldwide. The direct correlation between PDAC incidence, disease progression, and mortality highlights the critical need to understand the mechanisms by which PDAC cells rapidly progress to drive metastatic disease in order to identify actionable vulnerabilities. One such proposed vulnerability is epithelial mesenchymal plasticity (EMP), a process whereby neoplastic epithelial cells delaminate from their neighbours, either collectively or individually, allowing for their subsequent invasion into host tissue. This disruption of tissue homeostasis, particularly in PDAC, further promotes cellular transformation by inducing inflammatory interactions with the stromal compartment, which in turn contributes to intratumoural heterogeneity. This review describes the role of EMP in PDAC, and the preclinical target discovery that has been conducted to identify the molecular regulators and effectors of this EMP program. While inhibition of individual targets may provide therapeutic insights, a single 'master-key' remains elusive, making their collective interactions of greater importance in controlling the behaviours' of heterogeneous tumour cell populations. Much work has been undertaken to understand key transcriptional programs that drive EMP in certain contexts, however, a collaborative appreciation for the subtle, context-dependent programs governing EMP regulation is needed in order to design therapeutic strategies to curb PDAC mortality.

miR-1303 promotes the proliferation, migration and invasion of prostate cancer cells through regulating the Wnt/β-catenin pathway by targeting DKK3

MicroRNA-1303 (miR-1303) is involved in the tumorigenesis and progression of several cancers, and yet the role of miR-1303 in prostate cancer (PCa) and its underlying mechanism are unknown. To explore this issue, the present study aimed to use PCa tissues, cell lines and a PCa-engrafted mouse model to determine the expression and roles of miR-1303 in PCa. Furthermore, a series of experiments were conducted to explore the underlying mechanisms of action of miR-1303 in PCa cells. miR-1303 was demonstrated to be highly expressed in PCa tissues and cell lines. The level of miR-1303 expression was closely associated with higher Gleason scores and a more developed tumor stage in patients with PCa, and patients with higher levels of miR-1303 displayed a reduced overall survival rate. miR-1303 overexpression promoted the proliferation, migration and invasion of PCa cells. In vivo experiments showed that miR-1303 inhibition suppressed the growth of PCa tumors in mice. Additionally, dickkopf Wnt signaling pathway inhibitor 3 (DKK3) was identified as a target of miR-1303. Knockdown of miR-1303 suppressed the proliferation, migration and invasion of PCa cells, increased DKK3 expression, and inhibited the activity of the Wnt/β-catenin pathway. In conclusion, miR-1303 may promote proliferation, migration and invasion of PCa cells through activating the Wnt/β-catenin pathway by regulating DKK3 expression. These results indicated that miR-1303 may be considered as a potential biomarker for PCa treatment.

The clinicopathological and prognostic significances of Dkk3 expression in cancers: A bioinformatics analysis

BACKGROUND

Dkk3 protein attenuates the expression of Wnt3a, Wnt5a and LRP6, and their interaction, and interacts with βTrCP to suppress wnt/β-catenin pathway.

METHODS

We performed a bioinformatics analysis of Dkk3 mRNA expression through Oncomine, TCGA and Kaplan-Meier plotter databases up to July 10, 2017.

RESULTS

Up-regulated Dkk3 expression was higher in gastric, breast, and ovarian cancers than normal tissues (p< 0.05). Bitter's database showed a higher Dkk3 expression in ovarian cytoadenocarcinoma than clear cell adenocarcinoma (p< 0.05). Dkk3 was more expressed in ductal breast cancer in situ than invasive ductal breast cancer (p< 0.05), in mixed lobular and ductal cancer, and lobular cancer than ductal breast cancer (p< 0.05). In TCGA data, Dkk3 expression was lower in gastric cancers with than without Barret's esophagus (p< 0.05), in intestinal-type than diffuse-type cancers (p< 0.05), and in the cancers of elder than younger patients (p< 0.05). Dkk3 expression was higher in squamous cell carcinoma than adenocarcinoma (p< 0.05). Dkk3 expression was higher in ductal than lobular breast cancer, or in younger than elder patients with breast cancer (p< 0.05). According to Kaplan-Meier plotter, Dkk3 expression was negatively correlated with overall, progression-free, relapse-free or distant-metastasis-free survival rate of gastric, breast or ovarian cancer patients, but versa for lung cancer patients (p< 0.05).

CONCLUSION

Dkk3 expression might be employed as a potential marker to indicate carcinogenesis and histogenesis, even prognosis.

Hypoxia-induced autophagy promotes gemcitabine resistance in human bladder cancer cells through hypoxia-inducible factor 1α activation

Overcoming the chemoresistance of bladder cancer is a pivotal obstacle in clinical treatments. Hypoxia widely exists in solid tumors and has been demonstrated to contribute to chemoresistance through hypoxia-inducible factor 1α (HIF‑1α)-mediated autophagy in several types of cancer. However, it is unclear whether HIF‑1α-mediated autophagy and chemoresistance occur in bladder cancer. The present study demonstrated that HIF‑1α was overexpressed in 20 bladder cancer tissues compared with matched paracarcinoma tissues. Gemcitabine-induced apoptosis during hypoxia was significantly reduced compared with that observed under normoxic conditions. In addition, hypoxia activated autophagy and enhanced gemcitabine-induced autophagy. Combined treatment using gemcitabine and an autophagy inhibitor (3-methyladenine) under hypoxia significantly increased gemcitabine cytotoxicity. Furthermore, it was demonstrated that hypoxia-activated autophagy depended on the HIF‑1α/BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3)/Beclin1 signaling pathway. Suppressing HIF‑1α inhibited autophagy, BNIP3 and Beclin1, as well as enhanced gemcitabine-induced apoptosis in bladder cancer cells under hypoxic conditions. Consequently, the results of the present study demonstrated that hypoxia-induced cytoprotective autophagy counteracted gemcitabine-induced apoptosis through increasing HIF‑1α expression. Therefore, targeting HIF‑1α-associated pathways or autophagy in bladder cancer may be a successful strategy to enhance the sensitivity of bladder cancer chemotherapy.

LncRNA ADPGK-AS1 promotes pancreatic cancer progression through activating ZEB1-mediated epithelial-mesenchymal transition

OBJECTIVE

This study was conducted to investigate the effects of ADP dependent glucokinase antisense RNA 1 (ADPGK-AS1)/ miR-205-5p/ zinc finger E-box binding homeobox 1 (ZEB1) on PC cells.

METHODS

Differentially expressed lncRNAs and miRNAs in pancreatic cancer (PC) were identified by microarray analysis. In silico ceRNA analysis was conducted to find out the interactions among lncRNAs, miRNAs and mRNAs. Quantitative real-time PCR (qRT-PCR) was utilized to examine the expression of miR-205-5p and lncRNA ADPGK-AS1 in PC and non-cancerous cells. The association between miR-205-5p and ADPGK-AS1 as well as miR-205-5p and ZEB1 was determined by dual-luciferase reporter gene assay. After manipulating the expression of ADPGK-AS1, mir-205-5p and ZEB1 in PANC-1 and SW-1990 cells, cell proliferation, migration, invasion and apoptosis were respectively confirmed by cell counting kit-8 (CCK-8) assay, transwell assay and TUNEL. Western blot was applied to examine the expression of Epithelial-mesenchymal Transition-related proteins. In vivo experiment was conducted to further determine the effect of miR-205-5p/ZEB1 on tumorigenic ability of PC cells.

RESULTS

MiR-205-5p was low-expressed while ZEB1 and ADPGK-AS1 were high-expressed in PC tissues and cells compared with the normal. Dual-luciferase reporter gene assay proved that ADPGK-AS1 could directly target miR-205-5p and miR-205-5p could directly target ZEB1 3'UTR. The expression of MiR-205-5p was negatively correlated with proliferation, migration and invasion, and positively correlated with apoptosis rate of PC cells, while ZEB1 and ADPGK-AS1 had an inversed effect. Further in vitro and in vivo investigation indicated that epithelial-mesenchymal transition (EMT) could be restrained by miR-205-5p through targeting ZEB1. ADPGK-AS1 strongly promoted the tumorigenesis via downregulating miR-205-5p expression and induced the EMT process in vivo.

CONCLUSION

ADPGK-AS1 inhibited miR-205-5p and therefore promoted PC progression through activating ZEB1-induced EMT.

Methylation of the DKK3 promoter is associated with poor prognosis in patients with cervical adenocarcinoma

OBJECTIVE

The aim of this study was to investigate the mRNA of DKK3 (Dickkopf-3) in cervical adenocarcinoma, and to explore correlations between methylation status of the DKK3 promoter and biological behaviors of cervical adenocarcinoma.

METHODS

The mRNA expression level of DKK3 was detected by real-time quantitative reverse transcription PCR. Methylation-specific PCR (MSP) analysis was performed to detect the methylated degrees of the DNA of the DKK3 promoter.

RESULTS

The mRNA expression levels of DKK3 in cervical adenocarcinoma tissues were lower than those in adjacent normal cervical tissues. MSP detection found DKK3 promoter methylation was 38% in cervical adenocarcinoma tissues, while no normal cervical tissues were found to be methylated.FIGO staging and pelvic lymph node metastasis were identified as relative factors of methylation status of the DKK3 promoter. Multivariate analysis demonstrated methylation status of the DKK3 promoter was an independent prognostic indicator of cervical adenocarcinoma. Patients with methylated DKK3 promoter exhibited significantly shorter OS than those with an unmethylated DKK3 promoter.

CONCLUSIONS

The methylation status of the DKK3 promoter may indicate poor prognosis of patients with cervical adenocarcinoma.

Pharmacoepigenetics and pharmacoepigenomics of gastrointestinal cancers

Our understanding of the epigenetic changes occurring in gastrointestinal cancers has gained tremendous advancements in recent years, and some epigenetic biomarkers are already translated into the clinics for cancer diagnostics. In parallel, pharmacoepigenetics and pharmacoepigenomics of solid tumors are relevant novel, but emerging and promising fields. Areas covered: A comprehensive review of the literature to summarize and update the emerging field of pharmacoepigenetics and pharmacoepigenomics of gastrointestinal cancers. Expert commentary: Several epigenetic modifications have been proposed to account for interindividual variations in drug response in gastrointestinal cancers. Similarly, single-agent or combined strategies with high doses of drugs that target epigenetic modifications (epi-drugs) were scarcely tolerated by the patients, and current research has moved to their combination with standard therapies to achieve chemosensitization, radiosensitization, and immune modulation of cancerous cells. In parallel, recent genome-wide technologies are revealing the pathways that are epigenetically deregulated during cancer-acquired resistance, including those targeted by non-coding RNAs. Indeed, novel, less toxic, and more specific molecules are under investigation to specifically target those pathways. The field is rapidly expanding and gathering together information coming from these investigations has the potential to lead to clinical applications in the coming new years.

HINT2 downregulation promotes colorectal carcinoma migration and metastasis

Histidine triad nucleotide-binding 2 (HINT2), a member of the histidine triad proteins family, sensitizes cells to apoptosis in hepatocellular carcinoma. Here, we showed that HINT2 expression is lower in primary colorectal cancer (CRC) and metastasis tissues than in normal colorectal tissues, and that HINT2 abundance is inversely correlated with CRC tumor stage. Treating CRC cells with 5-aza-2′-deoxycytidine, a demethylating agent, upregulated HINT2, suggesting HINT2 downregulation is caused by methylation of the gene promoter. HINT2 downregulation increased tumor migration and invasion in vitro, promoted CRC cell metastasis in vivo, and increased expression of epithelial-to-mesenchymal transition (EMT) markers. Furthermore, HINT2 downregulation depended on hypoxia inducible factor (HIF)-2α-mediated transcriptional activation of zinc finger E-box-binding homeobox 1 (ZEB1). These results suggest that HINT2 downregulation promotes HIF-2α expression, which induces EMT and enhances CRC cell migration and invasion. HINT2 may thus a useful clinical indicator of CRC progression and metastasis risk.

Sesquiterpene binding Gly-Leu-Ser/Lys-"co-adaptation pocket" to inhibit lung cancer cell epithelial-mesenchymal transition

Sesquiterpene lactones (SL) have a wide range of applications in anti-tumor and anti-inflammatory therapy. However, the pharmacological mechanism of such substances is not clear. In this study, parthenolide (PTL) was used as an example to explore the anti-tumor effect of natural molecules and their common mechanism. We showed that PTL inhibited the proliferation and migration by reverse EMT via the ERK2/NF-κB/Snail pathway in vivo and in vitro. Interestingly, Multiple potential targets of PTL contain a Gly-Leu-Ser/Lys-“co-adaptation pocket”. This inspiring us analogies of PTL may also bind to these target proteins and play a similar function. Significantly, the Concept of co-adaptation pocket may help to increase the selectivity of drug research and development.

MicroRNA-92a promotes cell viability and invasion in cervical cancer via directly targeting Dickkopf-related protein 3

MicroRNA-92a (miR-92a) was recently reported to have an oncogenic role in cervical cancer; however, the underlying mechanism remains largely unclear. The present study aimed to investigate the expression, clinical significance and regulatory mechanism of miR-92a in cervical cancer. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) data indicated that miR-92a was significantly upregulated in cervical cancer tissues compared with matched adjacent non-tumor tissues (P<0.01). High expression of miR-92a was significantly associated with poor differentiation (P=0.031), advanced clinical stage (P=0.011) and lymph node metastasis (P=0.014), but not associated with age, tumor size and distant metastasis. Knockdown of miR-92a significantly inhibited the viability and invasion of cervical cancer HeLa cells, while overexpression of miR-92a significantly enhanced HeLa cell viability and invasion (P<0.01). Luciferase reporter assay identified Dickkopf-related protein 3 (DKK3) as a target gene of miR-92a, and the protein expression of DKK3 was negatively regulated by miR-92a in HeLa cells. Furthermore, overexpression of DKK3 significantly eliminated the stimulative effects of miR-92a on HeLa cell viability and invasion (P<0.01). Additionally, DKK3 was significantly downregulated in cervical cancer tissues compared with adjacent non-tumor tissues (P<0.01), inversely correlated to the miR-92a levels in cervical cancer tissues (P<0.01). In summary, the present study indicated that miR-92a promotes cell viability and invasion in cervical cancer, partly at least, via inhibiting the protein expression of DKK3. Therefore, the present study highlights the clinical significance of the miR-92a/DKK3 axis in cervical cancer.

Decreased expression of acetyl-CoA synthase 2 promotes metastasis and predicts poor prognosis in hepatocellular carcinoma

Metastasis is a serious risk that may occur during the treatment of hepatocellular carcinoma (HCC), preventing many patients from being surgical candidates and contributing to poor prognosis. Hypoxia has been proved an important factor of metastasis through the epithelial–mesenchymal transition (EMT) pathway. Acetyl‐CoA synthase 2 (ACSS2) provides an acetyl group for the acetylation of hypoxia‐inducible factor (HIF)‐2α, and this epigenetic modification affects the activity of HIF‐2α and the subsequent EMT process. Here, we showed that ACSS2 expression was negatively correlated with HCC malignancy. Knockdown of ACSS2 increased the invasion and migration ability of HCC cells and promoted EMT without increasing the total protein level of HIF‐2α, even in hypoxic conditions. The immunoprecipitation assay revealed downregulated acetylation levels of HIF‐2α after ACSS2 knockdown in hypoxic conditions, which resulted in enhanced HIF‐2α activity. Finally, decreased expression of ACSS2 was found to be related to advanced stage and poor overall survival and disease‐free survival rates in a cohort of patients with HCC. In conclusion, ACSS2 plays an important role in the acetylation process of HIF‐2α, which effectively modifies the activity of HIF‐2α under hypoxic conditions and greatly impacts on the prognosis of patients with HCC.

Annexin A2 inhibition suppresses ovarian cancer progression via regulating β-catenin/EMT

Annexin A2 is a member of the Annexin family that acts as a Ca2+-dependent phospholipid and membrane binding protein, which is associated with the survival and spread of multiple neoplasms. However, the function of Annexin A2 in ovarian cancer progression remains unclear. In this study, we aimed to investigate the role and underlying molecular mechanism of Annexin A2 in cell proliferation and invasion in ovarian cancer. We found that the mRNA expression of Annexin A2 was upregulated in ovarian cancer tissues and cell lines. In the loss-of-function of Annexin A2, β-catenin was indicated to be significantly suppressed and EMT constrained. Moreover, cell proliferation and invasion were both markedly inhibited by the downregulation of Annexin A2. Additionally, the overexpression of β-catenin obviously reversed the effect of Annexin A2 on EMT, and cell proliferation and invasion, indicating that Annexin A2 suppression regulated EMT through controlling β-catenin. Taken together, this study showed that Annexin A2 inhibition suppresses proliferation and invasion in ovarian cancer via β-catenin/EMT, proposing the potential role of Annexin A2 in the prevention and treatment of ovarian cancer.

Wnt10B is critical for the progression of gastric cancer

The family of Wnt proteins have been implicated in embryogenesis by regulation of cell fate and pattern formation, and also in human carcinogenesis. Wnt10B was previously shown to be involved in breast cancer development. The present study assessed the association of Wnt10B expression in human gastric cancer tissue specimens with clinicopathological data from these patients. Wnt10B expression in the regulation of gastric cancer cell proliferation and migration capacity in vitro was then investigated. The data revealed that Wnt10B mRNA and protein were upregulated in gastric cancer tissue samples and the upregulated Wnt10B mRNA was associated with gastric cancer metastasizing to lymph nodes. Knockdown of Wnt10B expression reduced gastric cancer cell proliferation and migration, as well as expression of a cell proliferation marker Ki67. Knockdown of Wnt10B expression inhibited tumor cell epithelial-mesenchymal transition by upregulation of E-cadherin and downregulation of N-cadherin. In addition, Wnt10B knockdown also suppressed tumor cell stemness by downregulation of octamer-binding transcription factor 4 and Nanog expression. The present data indicated that Wnt10B expression performs an important role in gastric cancer progression in vitro. Therefore, targeting of Wnt10B expression or activity may be investigated as a possible strategy for the control of gastric cancer.

A Novel Role of Dickkopf-Related Protein 3 in Macropinocytosis in Human Bladder Cancer T24 Cells

Dickkopf-related protein 3 (Dkk-3) is a potential tumor suppressor reported in various cancer entities. However, we found that Dkk-3 was exceptionally upregulated in bladder cancer T24 cells. To validate the biological role of Dkk-3 other than a tumor suppressor, we examined the function of Dkk-3 in T24 cells. Gene silencing of Dkk-3 inhibited cell growth through inducing G₀/G₁ cell-cycle arrest. Furthermore, Dkk-3 knock-down caused macropinocytosis accompanied by autophagy, which were canceled in part by their inhibitors 5-(N-ethyl-N-isopropyl) amiloride (EIPA) and 3-methyladenine (3-MA). The macropinocytosis was induced by the Dkk-3 knock-down when there were sufficient extracellular nutrients. On the other hand, when the nutritional condition was poor, the autophagy was mainly induced by the Dkk-3 knock-down. These data indicated that Dkk-3 has a role in modulating macropinocytotic and autophagic pathways, a distinct function other than a Wnt antagonist.

CDGSH Iron Sulfur Domain 2 Activates Proliferation and EMT of Pancreatic Cancer Cells via Wnt/β-Catenin Pathway and Has Prognostic Value in Human Pancreatic Cancer

Recently, increasing evidence has shown that CDGSH iron sulfur domain 2 (CISD2) is involved in the initiation and metastasis of several cancers. However, the evidence of its potential role in pancreatic cancer is still lacking. In our present study, CISD2 was found to be increased in pancreatic cancer samples and multiple cell lines. Moreover, statistical analysis revealed that a high level of CISD2 was related to advanced clinical stage, advanced T-stage, positive vascular invasion, positive distant metastasis, and larger tumor size. In addition, multivariate analysis suggests that CISD2 was an independent prognostic factor in pancreatic cancer. Importantly, downregulation of CISD2 was capable of inhibiting the survival and growth of pancreatic cancer cells. Mechanistic study showed that inactivation of the Wnt/β-catenin pathway contributed to the CISD2 deficit-induced death of pancreatic cancer cells. Furthermore, we showed that CISD2 silencing significantly inhibited EMT via the Wnt/β-catenin pathway. Finally, in nude mice, the CISD2 deficit suppressed the tumorigenesis of pancreatic cancer cells. Collectively, our study demonstrated that CISD2 could be an independent prognostic factor for pancreatic cancer and suggested that the CISD2/Wnt/β-catenin pathway contributes to the proliferation of pancreatic cancer cells and EMT, hinting at a novel promising molecular target in the therapeutic strategy for pancreatic cancer.

Silencing of Prrx1b suppresses cellular proliferation, migration, invasion and epithelial-mesenchymal transition in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive tumour subtype associated with poor prognosis. The mechanisms involved in TNBC progression remains largely unknown. To date, there are no effective therapeutic targets for this tumour subtype. Paired-related homeobox 1b (Prrx1b), one of major isoforms of Prrx1, has been identified as a new epithelial-mesenchymal transition (EMT) inducer. However, the function of Prrx1b in TNBC has not been elucidated. In this study, we found that Prrx1b was significantly up-regulated in TNBC and associated with tumour size and vascular invasion of breast cancer. Silencing of Prrx1b suppressed the proliferation, migration and invasion of basal-like cancer cells. Moreover, silencing of Prrx1b prevented Wnt/β-catenin signaling pathway and induced the mesenchymal-epithelial transition (MET). Taken together, our data indicated that Prrx1b may be an important regulator of EMT in TNBC cells and a new therapeutic target for interventions against TNBC invasion and metastasis.

Therapeutic potential of targeting acinar cell reprogramming in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a common pancreatic cancer and the fourth leading cause of cancer death in the United States. Treating this life-threatening disease remains challenging due to the lack of effective prognosis, diagnosis and therapy. Apart from pancreatic duct cells, acinar cells may also be the origin of PDAC. During pancreatitis or combined with activating KRas(G12D) mutation, acinar cells lose their cellular identity and undergo a transdifferentiation process called acinar-to-ductal-metaplasia (ADM), forming duct cells which may then transform into pancreatic intraepithelial neoplasia (PanIN) and eventually PDAC. During ADM, the activation of mitogen-activated protein kinases, Wnt, Notch and phosphatidylinositide 3-kinases/Akt signaling inhibits the transcription of acinar-specific genes, including Mist and amylase, but promotes the expression of ductal genes, such as cytokeratin-19. Inhibition of this transdifferentiation process hinders the development of PanIN and PDAC. In addition, the transdifferentiated cells regain acinar identity, indicating ADM may be a reversible process. This provides a new therapeutic direction in treating PDAC through cancer reprogramming. Many studies have already demonstrated the success of switching PanIN/PDAC back to normal cells through the use of PD325901, the expression of E47, and the knockdown of Dickkopf-3. In this review, we discuss the signaling pathways involved in ADM and the therapeutic potential of targeting reprogramming in order to treat PDAC.

Clinical significance of expression of miR-135b, LZTS1 and β-catenin in pancreatic cancer

AIM: To detect the expression of miR-135b, LZTS1 and β-catenin in pancreatic cancer in an attempt to explore their clinical significance.

METHODS: Locked nucleic acid in situ hybridization (ISH) and immunohisto-chemistry were used to detect the expression of miR-135b, LZTS1 and β-catenin proteins in 70 pancreatic cancer tissues and adjacent normal tissues, respectively.

RESULTS: The positive rate of miR-135b in pancreatic cancer was higher than that in adjacent tissues (71.4% vs 42.9%, P = 0.001). The positive rates of LZTS1 and β-catenin proteins in pancreatic cancer were significantly lower than those in adjacent tissues (34.3% vs 68.6%, 34.3% vs 74.3%, P < 0.05). Expression of miR-135b had a negative correlation with that of LZTS1 in pancreatic cancer (r = -0.61, P < 0.05), but miR-135b expression had no significant correlation with β-catenin (r = 0.06, P > 0.05). LZTS1 expression had a positive correlation with that of β-catenin (r = 0.37, P < 0.05). Expression of miR-135b, LZTS1 and β-catenin was closely related with lymph node metastasis and clinical stage (P < 0.05), but had no correlation with patient age, sex, tumor site or histological grade (P > 0.05).

CONCLUSION: miR-135b is highly expressed in pancreatic cancer, while the expression of LZTS1 and β-catenin is decreased. Up-regulated expression of miR-135b may participate in the development of pancreatic cancer by down-regulating the expression of LZTS1 protein.

TGFβ1-Smad3-Jagged1-Notch1-Slug signaling pathway takes part in tumorigenesis and progress of tongue squamous cell carcinoma

BACKGROUND

TGFβ1 and Smad3 play an important role in the process of EMT. TGFβ1 regulates the expression of Jagged1 by modulating Notch signaling. Jagged1 is related to tumor invasion, metastasis, chemotherapy resistance, and tumor immune escape. The aims of this study are to examine deregulation of TGFβ1-Smad3-Jagged1-Notch1-Slug signaling in TSCC and to investigate its roles in TSCC progression.

MATERIALS AND METHODS

Notch1, Smad3, Jagged1 and Slug proteins and mRNA expression were detected in specimens from 89 cases of patients. We analyzed the correlation between their expressions and histological grade, clinical stage and lymph node metastasis.

RESULTS

Notch1, Smad3, Jagged1 and Slug mRNA expressions in TSCC were higher than normal tissue (P <0.05). The protein expression of Notch1 and Smad3 in TSCC were higher (χ(2) =7.30, P <0.01 and χ(2) = 5.84, P <0.05). Notch1 and Smad3 expressions were correlated with clinical stage (χ(2) =18.81, P<0.01; χ(2) =22.29, P<0.01), but not Jagged1 (χ(2) =0.53, P>0.05). The Slug protein expression was correlated with clinical stage. The positive rate of Notch1 was higher in lymph node metastases positive cases (χ(2) =7.30, P<0.01). Moreover, higher expression of Jagged1 was found in lymph node positive cases (χ(2) =10.82, P<0.01).

CONCLUSIONS

The key protein expression in TGFβ1-Smad3-Jagged1-Notch1-Slug signaling pathway significantly correlated with the clinicopathological features of TSCC patients. It's potential as a biomarker and a novel therapeutic target for TSCC patients at risk of metastasis. It may play an irreplaceable role in TSCC progression which may attribute to promoting EMT which enhances cell migration, invasion and metastasis.